The Parkfield, California, Earthquake Experiment

The Parkfield Experiment is a comprehensive, long-term earthquake research
project on the San Andreas fault. Led by the USGS and the State of
California, the experiment's purpose is to better understand the physics
of earthquakes - what actually happens on the fault and in the surrounding
region before, during and after an earthquake. Ultimately, scientists hope
to better understand the earthquake process and, if possible, to provide a
scientific basis for earthquake prediction. Since its inception in 1985,
the experiment has involved more than 100 researchers at the USGS and
collaborating universities and government laboratories. Their coordinated
efforts have led to a dense network of instruments poised to
"capture" the anticipated earthquake and reveal the earthquake
process in unprecedented detail.

Hypothesis

Moderate-size earthquakes of about magnitude 6 have occurred on the
Parkfield section of the San Andreas fault at fairly regular intervals -
in 1857, 1881, 1901, 1922, 1934, and 1966. The first, in 1857, was a
foreshock to the great Fort Tejon earthquake which ruptured the fault from
Parkfield to the southeast for over 180 miles. Available data suggest that
all six moderate-sized Parkfield earthquakes may have been
"characteristic" in the sense that they all ruptured the same
area on the fault. If such characteristic ruptures occur regularly, then
the next quake would have been due before 1993.

These pages describe the scientific background for the experiment,
including the tectonic setting at Parkfield, the historical earthquake
activity on this section of the San Andreas fault, the monitoring and data
collecting activities currently being carried out, and plans for future
research. Data are available to view in real-time and download.

Scientific Advances

While the greatest scientific payoff is expected when the earthquake
occurs, our understanding of the earthquake process has already been
advanced through research results from Parkfield. Some of the highlights
are described.

Data

Real-time data from instrumentation networks running at Parkfield are
available for viewing and downloading.

Parkfield Earthquake Shake Table Exhibit

The exhibit was a geologically interactive, seismic machine earthwork temporarily installed in Parkfield in 2008. Rogers presented the history, conceptual premise, documentation of the work, and also put forward the idea of how early 21st century cultural practice could be used to encourage earthquake awareness and preparedness.

Lessons From the Best-Recorded Quake in History

New data from the 2004 Parkfield earthquake provide important
lessons about earthquake processes, prediction, and the hazards
assessments that underlie building codes and mitigation policies.

The Town of Parkfield,
located on the San Andreas fault in central California, has been the
site of an intensive, multidisciplinary earthquake study since the late
1970's. The goal is to observe the fault and surrounding crust at close
range at the time before, during and after an earthquake, to better
understand the earthquake process and provide a scientific basis for
earthquake prediction. Close-up map of Parkfield
study area.